1. Field of the Invention
The present invention relates to a heat treatment apparatus and a method of controlling the same.
2. Description of the Related Art
A batch-type heat treatment apparatus is known as a heat treatment apparatus for performing a heat treatment, such as a film formation process, an oxidation process, and a diffusion process, on a semiconductor wafer.
Recently, with an increase in size of a semiconductor wafer and a decrease in process size of an integrated circuit, various heat treatments require more precise thermal control. Conditions required for thermal control performed in a batch-type heat treatment apparatus may include a ramping rate with high temperature uniformity during ramping, little overshooting of a temperature, temperature stability for achieving a target temperature in a short time, and the like.
Thermal control performed in a batch-type heat treatment apparatus is performed by one model that is previously set in a processing recipe. One model includes a plurality of sub-models according to temperature zones. The sub-models to be used are changed according to a setting temperature and an actual temperature (for example, Patent Reference 1 and Patent Reference 2).
However, since an optimum model varies according to desired heat treatment conditions, it is difficult to realize an optimum temperature characteristic by changing the model only in the temperature zones.
3. Prior Art Reference
(Patent Reference 1) Japanese Laid-Open Patent Publication No. 2008-218558
(Patent Reference 2) Japanese Laid-Open Patent Publication No. 2009-81260